Parabolic trough technology
The first choice for large-scale solar power generation

Concentrated Solar Power – Clean and predictable electricity generation around the clock

Concentrated Solar Power (CSP) technology uses energy from the sun to generate heat, which is used in steam cycles to produce electricity. The technology is particularly efficient in regions with high direct solar irradiation, encompassing the earth’s sunbelt on both sides of the equator to 35 degrees latitude. CSP plants are used in a similar manner like conventional steam power plants. The key difference is that CSP plants use emission-free, clean solar radiation to produce heat instead of fossil or nuclear fuels. Amongst all CSP technologies, the parabolic trough technology has the longest commercial track record of almost 30 years.

Parabolic trough power plants are suitable for large-scale use in the range of 10 to 300 megawatts electrical output and can replace conventional thermal power plants without any qualitative changes in the electricity grid structure. Due to the option of thermal storage or hybridization, the turbines of CSP plants can also produce power in low solar radiation periods and at night, delivering power reliably, on a planned schedule and in a way that keeps the grids stable.

How parabolic trough power plants work

In a CSP plant, the generation of heat mostly depends on the level of solar irradiation. In order to achieve the necessary temperatures, solar radiation is concentrated in parabolic trough arrays. These troughs can be more than 600 meters in length and are made of parabolic shaped mirror segments. The troughs track the sun over the course of the day and focus the solar radiation along the focal point of the mirrors onto the “heart” of a CSP plant: specially coated, evacuated receiver tubes. The receiver tubes convert solar radiation into thermal energy, and therefore their durability and efficiency are crucial for the sustainable profitability of the entire solar plant. A heat transfer fluid, which circulates through the receiver, is heated up and then used to generate steam.

How parabolic trough power plants work

The overall power plant efficiency is determined by the maximum operating temperature of the heat transfer fluid used. The most commonly used oil-based heat transfer fluids operate at temperatures up to 400°C. A key innovation to further improve the plant efficiency is the usage of heat transfer fluid that allows operation up to 550°C, such as molten salts or direct steam.